The Low Sedimentation Speed of Cryptosporidium Oocysts: A Further Explanation for Waterborne Outbreaks

Abstract

The very low sedimentation speed of Cryptosporidium parvum, C. muris, and C. baileyi oocysts is reported. The regression of the sedimentation speed of oocysts in fecal suspension and tap water could be described by exponential equations. Depending on temperature, sedimentation media, and species, between 0.5 – 3.5 days were needed for the total disappearance of oocysts from the upper layer of water. This characteristic might be attributed to directive selection of cryptosporidium spp. For low density through the way of transmission. The settlement of C. Parvum was slower than that of C. baileyi or C. muris. The slow disappearance of Cryptosporidium oocysts from sewage, surface waters, and public water supplies could be one of the major factors responsible for the transmission of this parasites via drinking water.